The "Childmyths" blog is a spin-off of Jean Mercer's book "Thinking Critically About Child Development: Examining Myths & Misunderstandings"(Sage, 2015; third edition). The blog focuses on parsing mistaken beliefs that can influence people's decisions about childrearing-- for example, beliefs about day care, about punishment, about child psychotherapies, and about adoption.
See also http://thestudyofnonsense.blogspot.com

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Tuesday, November 8, 2016

Blinding Them with Science: The Epigenetics Issue

The idea of epigenetic factors—events that shape the
ways genetic material is expressed in the developing individual—goes back a
long way. For example, the geneticist Waddington suggested what he called an
“epigenetic landscape”, in which factors like exposure to infection could push
development into a different pathway from what might otherwise have been. These
different pathways, once entered on, would further direct the course of
development and might take the individual farther and farther from the
developmental outcome that would have occurred without the infection.

Within the last half-century, it has become apparent
that a range of factors can change the ways in which genes are expressed in individual
development. One of these factors, a biochemical change called methylation,
alters matters like the number of repeats of a genetic pattern in the
individual genome. The very interesting thing about methylation is that this
genetic change sometimes is, and sometimes is not, apparent in an individual’s
developmental outcomes. For example, the gene responsible for Fragile X
syndrome (a problem characterized by mental retardation and behavior problems)
has already begun to change several generations before any developmental
problems are apparent. A Fragile X patient’s mother and grandmother already had
genetic changes at work, but these had not advanced to the point where
development became atypical. (Note, by the way, that when genetic problems of this
kind occur, some, like Fragile X, develop only in the maternal line, while
others develop only in the father’s and
grandfather’s genomes.)

Fast forward now to 2004, when researchers reported
that rat pups whose mothers licked them more (as well as showing more of other
maternal behavior) had fewer genetic methylation events than those with less
attentive mothers, that this situation persisted into adulthood, and that the
less-mothered pups had worse reactions to stress in adulthood. The researchers,
Szyf and Meaney, also that by cross-fostering pups (temporarily giving the
less-mothered pups to more attentive mothers, and trading those mothers’
original pups to the inattentive mothers) they could actually reverse the
differences between the groups, thus showing that the pups’ original genetic
make-ups had not caused the differences between groups. As far as I can see,
these researchers assumed that all effects had to do with the attentive and
inattentive mothers’ behavior; they do not seem to have analyzed the milk of
each mother for differences that might influence genetic material and
development of the pups.

Very quickly, a rush to apply the rat studies to human
beings began. Look, people said, early bad experiences change individuals, and
what’s more we can fix them! For example, at www.center4familydevelop.com/Epigenetics.pdf,
where attentive rat mothers are anthropomorphized as “conscientious”, Arthur Becker-Weidman uses epigenetic studies
to make the following claim:

“One clear implication of this research is that the
Attachment-Facilitating Parenting with Attachment-Focused Psychotherapy can be
instrumental in demethylating important genes and, therefore, ‘resetting’ the
stress response system to be within a more normal range. It is clear that harsh
parenting methods, methods that are shaming, blaming, and critical only serve
to reinforce negative expectations and the unresponsive stress-response
system’s reset mechanism [N.B. I do not claim to understand this last bit; I’m
just reporting the news here. J.M.]. Parenting methods that are grounded in a
focus on relationships and connection of an emotionally meaningful and joyful
nature may reset the stress response system by its [sic] effects.”

Let’s examine this claim under a couple of strong
lights. The first has to do with extrapolation from rats to human beings (or
even from a particular strain of rats to other strains of rats). As I pointed
out on this blog some years ago, if Harry Harlow had used a different type of
monkey, the results of his work, and their capacity to support Bowlby’s
attachment theory, might have been quite different (http://childmyths.blogspot.com/2011/09/you-can-pick-your-friends-but-you-cant.html).
Generalization from one species to another takes careful work to substantiate
it, especially when the species are so different, with much different life spans
and times to reach reproductive maturity. Rats take about 30 days from birth to
reproductive age, as opposed to 12-14 years for human beings, so how do we
decide which part of a rat’s early development is parallel to any part of human
development? In addition, the work of rat mothers involves building a nest,
licking the young, positioning herself so they can nurse, and retrieving them
in response to their squeaks if they manage to get out of the nest. If
disturbed by noises or other animals, the rat mother may well eat the babies (and
although I suppose this may have happened among humans, even Greek myths
usually concentrate on mothers who serve the kids up to their fathers for
dinner). I leave it to readers to think about parallels to human infant care,
but want to point out that humans typically have one baby at a time and
concentrate on that baby’s care, with at least a year ordinarily intervening
before a new baby arrives—humans are not caring for a litter of young ones as
rats do.

To go on, let’s look at the statement that a kind of
intervention can be instrumental in methylating certain genes. This is a rather
staggering leap of logic. For one thing, it suggests that behavioral change through psychotherapy results
from change at the genetic level, caused by the therapy. As we have yet to
understand any specific relationships between human genes and human behavior, the
suggestion that changed genes mean changed behavior, and vice versa, is far
from warranted. Unless we are to assume that all learning results from genetic
change (which would be absurd), this cannot be a correct connection to make.
Even if we were to have evidence that some intervention changed some genetic material,
which we do not, it would be necessary to show systematic evidence supporting
the claim that any other intervention had the same effect.

In addition, in this particular case of
generalization, there seems to be a questionable assumption that human beings
can at any point in their development be influenced in their genes and behavior
by treatment, in ways parallel to the effects of cross-fostering on rat pups
very early in their development. It’s curious, too, that on an Internet site so
devoted to the ill effects of adoption on development, the comparison is made
to cross-fostering and reversal—these rat pups were reported to do better with “good”
mothers rather than to suffer from separation from the birth mother.

Unfortunately,
it is becoming all too common to see claims that because established research
evidence supports part of an idea or a practice, it can then be assumed that
the whole idea or practice is equally evidence-based. When this approach is applied to epigenetics,
some wild conclusions can be drawn in the course of attempts to translate lab
findings into social recommendations (as Juengst et al noted in Trends in Genetics, https://www.researchgate.net/publication/265853557_Serving_Epigenetics_before-Its-Time).

(My thanks to Yulia Massino for suggesting this
source.)

The lessons of “blinding with science” are applicable
not only to epigenetics, but to a variety of other attempts to bring scientific
concepts to bear on what are essentially pseudoscientific ideas and practices.
One example is the effort to bring quantum mechanics into explanations of
various “energy therapies”. Another is the enormous proliferation of supposedly
brain-based educational interventions that emerged from the “split-brain” work
of Roger Sperry (for an account of this, see Michael Staub, “The other side of
the brain: The politics of split-brain research in the 1970s-1980s”. History of Psychology, 19(4), 259-273).

Moral: Before hurrying to conclusions about
application of research findings to the more complicated world outside the lab,
we need to ask ourselves—“exactly what does the research have to do with the
practical problem we’re worried about?” Often the answer will be “Nothing—yet.”
Realizing that can help keep us from treatment scams of which there are so many
looking for suckers.

About Me https://en.wikipedia.org/wiki/Jean_Mercer

Jean Mercer has a Ph.D in Psychology from Brandeis University, earned when that institution was 20 years old (you do the math). She is Professor Emerita of Psychology at Richard Stockton College, where for many years she taught developmental psychology, research methods, perception, and history of psychology. Since about 2000 her focus has been on potentially dangerous child psychotherapies, and she has published several related books and a number of articles in professional journals.
Her CV can be seen at http://childmyths.blogspot.com/2009/12/curriculum-vitae-jean.mercer-richard.html.